Motor

Abstract

A motor includes a stator that includes a stator core and coils. The stator core is formed of a magnetic material and has a plurality of teeth arranged at intervals in a circumferential direction. The coils are formed of electrically-conductive windings wound around the teeth. Moreover, the motor also includes a rotor having a plurality of magnets arranged in radial opposition to the stator core and at intervals in the circumferential direction. The rotor is configured to rotate upon supply of electric current to the coils. Furthermore, the motor also includes a plurality of pseudo-teeth formed of a magnetic material and each located in a circumferentially intermediate area between a circumferentially-adjacent pair of the teeth. The pseudo-teeth are arranged so as to be concentrated in a part of the stator core in the circumferential direction.

What is claimed is: 
     
       1. A motor comprising:
 a stator including a stator core and coils, the stator core being formed of a magnetic material and having a plurality of teeth arranged at intervals in a circumferential direction, the coils being formed of electrically-conductive windings wound around the teeth; 
 a rotor having a plurality of magnets arranged in radial opposition to the stator core and at intervals in the circumferential direction, the rotor being configured to rotate upon supply of electric current to the coils; 
 a plurality of pseudo-teeth formed of a magnetic material and each located in a circumferentially intermediate area between a circumferentially-adjacent pair of the teeth, the pseudo-teeth being arranged so as to be concentrated in a part of the stator core in the circumferential direction; and 
 a plurality of sensors each of which is located in a circumferentially intermediate area between a circumferentially-adjacent pair of the teeth, the sensors being arranged so as to be concentrated in a part of the stator core in the circumferential direction, the part of the stator core where the sensors are concentrated being different from the part of the stator core where the pseudo-teeth are arranged, 
 wherein 
 a sum of a total number of the pseudo-teeth and a total number of the sensors is set to be smaller than a total number of the teeth. 
 
     
     
       2. The motor as set forth in  claim 1 , further comprising a plurality of terminals each of which is located in a circumferentially intermediate area between a circumferentially-adjacent pair of the teeth, the terminals being arranged so as to be concentrated in a part of the stator core in the circumferential direction, the part of the stator core where the terminals are concentrated being different from both the part of the stator core where the pseudo-teeth are arranged and the part of the stator core where the sensors are arranged. 
     
     
       3. The motor as set forth in  claim 2 , wherein
 the plurality of terminals comprise circuit-board connection terminals, 
 the circuit-board connection terminals are arranged in the circumferential direction of the stator core on the side where the sensors are arranged, 
 a circuit board is arranged on one side in an axial direction of the stator core, and 
 the circuit-board connection terminals and the sensors are connected with the circuit board. 
 
     
     
       4. The motor as set forth in  claim 3 , wherein
 the plurality of terminals comprise, in addition to the circuit-board connection terminals, neutral-point terminals that connect between the windings, and 
 a sum of the total number of the pseudo-teeth, the total number of the sensors, a total number of the circuit-board connection terminals and a total number of the neutral-point terminals is set to be equal to the total number of the teeth. 
 
     
     
       5. The motor as set forth in  claim 2 , wherein
 an insulator, which is formed of an electrically-insulative material, is mounted to the stator core, and 
 to the insulator, there is mounted a busbar by which the sensors and the terminals are supported.